Combustion apparatus



Feb. 18, 1930. s. D. SUNDSTRAND 7 1 333 I I COMBUSTION APPARATUS FiledFeb. 25, l926 2 Sheets-Sheet l 2106mm C7127. fiundjtnmd, a; M mam Feb.18, 1930. a. D. SUNDSTRAND 3 COMBUSTION APPARATUS 3 Filed Feb. 25, 19262 Sheets-Sheet 2 Patented Feb. 18, 1930 UNITED STATES PATENT OFFICEGUSTAF DAVID SUNDSTRAND, OF ROCKFORD, ILLINOIS, ASSIGNOR, BY MESNEASSIGN- MENTS, TO SUNDSTRAND ENGINEERING COMPANY, OF ROCKFORD, ILLINOIS,A COR- PORATION OF ILLINOIS COMBUSTION APPARATUS Application filedFebruary 25, 1926. Serial N'o. 90,452.

This invention relates to a method of combustion and to combustionapparatus for oil burners and especially to apparatus havlng bowls orbasins adapted for use in domestlc heaters, although the usefulness ofthe method and of such apparatus is not necessarily so limited.

In domestic heating some of the chief objections to the presentuse ofoil burners is the noise attendant upon the supply of fuel and airduring combustion, the production of odors, soot and smoke frominefiicient combustion, and the resultant increased cost of fuel onaccount of the low efficiency.

The present invention aims to provide a combustion bowl and a fuelnozzle so designed and so related, with due regard for the particularfurnace, that the combustion is quiet, clean, complete and efficient.

Another object is to provide an arrangement which prevents localizationof combustion; and which provides for a progressive combustion by aprogressive association of the fuel with the oxygen of the mixed air andcombustion products.

Another object of the invention is to provide a whirling flame so thatthe path of the gases through the furnace is relatively long whereby topermit slow, efficient and complete combustion in the fire box.

Other and ancillary objects and advantages will be found stated in thefollowing description of the invention. In the accompanying drawingsthere are shown two specific embodiments of the invention given for thepurpose of explaining the principles thereof and to show the manner inwhich the invention may be applied practically.

The form shown in Sheet 1 of the accompanying drawings is divisionalfrom applicants copending application Serial N 0. 575,642 filed July 17,1922, and the form shown on Sheet 2 is divisional from applicantscopending application Serial N 0. 72,634, filed December 2, 1925, thelatter form representing refinements in design and adjustments in therelation of the parts resulting from the intervening years of practicalexperience.

In the drawings, Figure 1 represents a plan view of the burner bowl andnozzle.

Fig. 2 represents a vertical cross section on the line 2-2 of Fig. 1.

Fig. 3 is a plan View of an alternative form of bowl.

Fig. 4 is a longitudinal section of the nozzle construction.

Fig. 5 is a side elevation of the improved bowl and nozzle, afragmentary portion of the furnace being shown.

Fig. 6 is a view of the nozzle mounting on the front of the furnace,showing an adjustment feature.

Fig. 7 is a vertical cross section of the bowl taken on the line 77 ofFig. 8.

Fig. 8 is a plan view of the structure shown in Fig. 5.

It is to be understood that the devices of the drawings are subject tofurther modifications and to adjustments in the relations of the bOWlsand nozzles. It is further to be understood that the invention is nothereby limited to the exact disclosures, but is to be defined andlimited only by the scope of the appended claims.

Referring to the earlier embodiment of the invention, there is providedwithin the combustion chamber of the furnace a bowl 10 which rests onthe grate bars 11 of a furnace indicated in part at 12 for the purposeof showing the general relationship to the furnace. In practice thefiredoor of the furnace is removed and a special closure 13 (Fig. 2) issubstituted therefor, said closure having an opening 14 through whichthe horizontal section 15 of an air conduit extends. To the inner end ofthe section 15 is secured an upright conduit section 16, the lower endof which is connected to the inlet 17 of the burner bowl 10. The bowl 10which virtually constitutes a fire box, is of such size that it may beinserted into the furnace through the fire door opening covered by thespecial fire door 13;

and it is adapted to be set directly upon the grate of the furnace. Ifthe grate of a given furnace be relatively low, a layer of suitablematerialmay be placed between the grate and the bowl to support thelatter at the proper height. It will be seen that it is unnecessary toremove the grate and to construct a fire box within the furnace, thusgreatly lessening the expense for labor and materials in theinstallation of the apparatus.

As shown in the plan View entitled Fig. 1, the burner bowl 10 iscircular and the inlet 17 is tangential thereto. The rim of the burnerbowl is undercut to provide an annular concave internal wall 18 asindicated in Fig. 2, thus providing an internal annular lip 19 near theupper edge of the bowl. As shown in Fig. 2, the bowl is highest at apoint adjacent to the inlet 17 and lowest at a point diametricallyopposite such highest point.

Referring to Fig. 1, the dotted line 20 indicates the vertical plane ofthe axis of the inlet 17; the dotted line 21 designates a planeperpendicular to the plane 20; and the dotted line 22 denotes a planeapproximately 15 away from the plane 21 in a direction remote from theintake 17. The highest point of the bowl is approximately at the pointwhere the line 22 passes through the edge of the bowl nearest the inlet17; and the diametrically opposite point where the line 22 pass-esthrough the edge of the bowl is the lowest point of the bowl. The rim ofthe bowl is tapered on both sides from the highest point and the lowestpoint.

I have found that a bowl twelve inches in diameter and with a singleinlet 17 gives satisfactory results in ordinary installations. Ininstallations requiring the production of a relatively large amount ofheat, a larger bowl may be employed to advantage. Fig. 3 represents abowl 1O which, in practice, may be approximately nineteen inches indiameter, and which has two diametrically opposite air inlets 17 and 17The port 17 communicates with the pipe 16 through a passage 17 in thewall of the bowl.

Through the fire door closure 13 there extends a feed pipe 23 1). Thispipeextends through an opening in the closure 13 and carries at itsinner end, within the furnace, a nozzle 24 (Figs. 1 and 2) located onthe bowl-side of the inlet. The nozzle is provided with a dischargeorifice 25 arranged to direct fuel in the'form of a mixture of oil andair downwardly into the combustion bowl 10. It has been found that thepoint at which the combustible mixture strikes the bowl should bear acertain definite relation to the bowl and the inlet 17 in order that thebest results may be obtained. When this combustible mixture is directedto the area marked 26 in Fig. 1, excellent results are obtained. If themixture be directed to other points in the bowl smoke is produced orthere is an increase in noise; or the flame is diminished or the evendistribution of the flame around the bowl is affected; or there may be aspace at the edge of the bowl where there will be no flame at all. Itappears that the combustible mixture from the nozzle 24 should bedirected into the air issuing from the inlet 17 at a point near saidinlet in order to obtain the best results to eliminate the objectionablefeatures just noted. There is further a very decided advantage inlocating the nozzle 24 above the bowl 10 and directing the mixture downinto the bowl as distinguished from locating the nozzle in the edge ofthe bowl, as, for example, in or near the inlet 17. hen the nozzle islocated as last stated, the flame appears around the edge of the bowlbut the central part of the bowl is dark; in other words, all of thecombustion occurs near the periphery of the bowl and combustion isimperfect, soot accumulating upon the central portion of the bottom ofthe bowl; whereas when the nozzle 24 is located above the bowl so as todirect the mixture down into the bowl near the inlet 17, the bowl iscompletely filled with flame, there is no accumulation of carbonanywhere in the bowl, and the flame is whiter andmuchlarger, and risesfrom the center of the bowl as well as being spread outward from itsedges. Moreover, the nozzle is in a position where it is relatively cooland therefore where oil will not carbonize on the nozzle.

On account of the whirling. movement of the air and combustible mixturewithin the bowl 10, the major part of the resulting flame would escapeover the edge of the bowl at or near the place where the incoming airfrom the inlet 17 strikes the edge of the bowl were it not for thetapered formation of the wall of the bowl. lVith the tapered formationhereinbefore described, the flame is caused to circulate around the bowland escape over the edge equally in all radial directions, so that evendistribution of heat from all parts of the bowl is obtained.

The discharge orifice 25 of the nozzle 10 is preferably of relativelylarge size, as, for example, from one-eighth to three-sixteenths of aninch in diameter. In prior constructions where a relatively largedischarge orifice was provided, a needle valve located adjacent to thedischarge orifice was employed to regulate the discharge, thus greatlyreducing the effective size of the discharge orifice and, in practice,so constricting the passage as to produce clogging when heavy oil wasburned. It will be observed that in my construction no needle valve orthe like is employed to restrict the discharge passage. As shown in Fig.4, the end of the nozzle 24 opposite to the discharge orifice 25 has anopening 26 which is closed by means of a screw plug 27. The opening 26is a necessary incident of the method of manufacturing the nozzle, butif for any reason the orifice 25 should become clogged the screw plug 27may be removed and an implement inserted to clean the orifice. Thenozzle merely provides for the emission and direction of fuel,preferably as a mixture of oil and air traveling under pressure throughthe conduit 23. Reference should be made to the above mentionedcopending application for the details of the mixture and pressureproducing apparatus, the character of which does not bear upon thepresent invention.

Any suitable means may be employed to ignite the combustion mixture, agas flame being employed for that purpose in the pres ently describedembodiment of my invention. A gas pipe 28 runs parallel to the feed pipe23 and carries a pilot structure 29 which emits a flame at the opening30. The pilot flame is directed downwardly so as to strike the jet ofcombustible mixture issuing from the nozzle 24, whereby said jet isignited. It will be seen that the pilot light is located remote from thecombustion bowl 10 and therefore will not be blown out by the current ofair issuing from the inlet 17.

In practice when the apparatus is to be installed the workman insertsthe combustion bowl 10 through the fire door opening and connects theconduit section 15 to the air supplying means (not shown). The

workman then provides a pipe 23 of proper length, screws-the nozzle 24upon one end of said pipe, inserts that end into the furnace and screwsthe other end into suitable mixture supply means, the nozzle 24 beingpositioned so as to direct the jet of combustible mixture to the properpoint within the combustion bowl. The workman then mounts the pilotlight structure 29 upon the gas pipe 28. Connections having been made tosources of supply of fuel oil, gas and air, the apparatus is then readyfor operation. The damper in the ash-pit door is preferably kept closed.Suitable means are utilized for adjusting the quantity of oil and air asdescribed in the parent application Serial No. 575,642.

In the foregoing description of the earlier form, reference is made tocertain features l which have been dispensed with in arriving at theimproved and preferable embodiment of the invention. The improved form,however, maintains the same general relatlon of the parts and involvesthe same principles of construction and operation.

In the newer form a bowl is provided with an inner concave wall 36 andan inner annular lip 37 at the top of the bowl. A tangential air inlet38 is provided which is in communication with an air supply conduit 39.The air conduit enters the furnace through the ash-pit opening 39 and isdirected upwardly towards the bowl, the latter be ing located in thelower portion of the combustion chamber of the furnace. A verticalsleeve 40 is formed integrally with the conduit 39 to receive asupporting leg 41 for the bowl. A vertical web 42 is cast with theconduit and is integral with a peripherally flanged bottom plate 43 ontowhich the bowl casting is placed. The plate 43 has an elongatedreservoir 44 formed therein into which is threaded a drain pipe 45 forremoving oil therefrom. The pipe 45 is coupled with a pipe 46 leading toa suitable safety device (not shown). A hole 47 is formed in the bottomof the bowl to drain excess oil therefrom into the reservoir to bedrained away for operation of the safety device in a well known manner.An inclined drip board 48 is cast with the bowl on the heater-front sideand is so designed as to underlie the nozzle and to gather drippingstherefrom, which, if they accumulate, will thus enter the oil reservoir44.

The nozzle 50 in the present instance differs from the above describednozzle 24 in that it receives a separate supply of oil at 51 and ofspraying air at 52, emitting, however, a spray mixture of oil and air asin the first instance. The nozzle is carried by a bracket member 53which is rigid with a plate 54 pivotally mounted on a closure plate 55secured to a fire doorway frame 56. The furnace is represented generallyby the numeral 57 merely to show the relation of the parts to thefurnace walls.

The pivotal plate 54 is shown clearly in Fig. 6 and is arranged to swingangularly in a vertical plane on plate 55 for the purpose of adjustingthe angular direction of the spray, thus to cause it to impinge at theproper point in the bowl 35. The plate 54 swings about the axis of asleeve 58 and is provided with arcuate slots 59 and clamping screws 60.The spray is directed along the line designated 61 to impinge upon theair entering the bowl in front of the inlet 38. A standard 62 aids insupporting the parts at the furnace door.

There is an electric ignition device associated with the improved formwhich is indicated generally at 63, having spark points 64 located inthe path of the fuel issuing from the nozzle. mounted within the sleeve58 wherein it is preferably made adjustable.

In the operation of apparatus embodying the present invention acontrollable lowpressure large-volume supply of air is furnished to thebowl at the inlet. The air thus swirls around and is emitted bothupwardly and radially from the bowl over the annular lip thereof.v Theignited oil spray is directed downwardly into the bowl at a considerablevelocity to impinge upon the entering air near the inlet. The cone ofthe spray is, of course, somewhat elongated and displaced because of themoving air. Combustion, of course, takes place as the swirling gasescirculate and rise. There being more oxygen near the bottom and greaterheat and less oxygen at the top, the fuel is thus progressivelyintroduced into the air supply,

The ignition device is thus ensuring perfect combustion. The spraypassing through the hot rising and whirling gases readily becomes heatedand in part vaporizes, such action taking place along the downward pathof projection. This distributes the volatilizing area and contributes tothe prevention of the roaring sound. The projection of the oil acrossthe area over the bowl ensures that the above named advantages obtain.In the first form the oil is directed substantially across the wholearea of the bowl while in the second form the oil is projected acrosssubstantially half of the area of the bowl. Each gives satisfactoryresults, however. The exact location of the nozzle in respect tolatitude and as to height above the bowl is in part determined by theinterior form of the fire box in which it is to be placed, as well as bythe size of the installation.

The method of combustion employed in the two forms of apparatus abovedescribed is such as to minimize the noise and to increase theefficiency of combustion by impinging the oil spray upon a stream ofair, the oil being directed ang ularly into the air stream andpreferably somewhat in the same direction. The arrangement of the bowlor basin in which combustion takes place in part is such as to provide along combustion path. The arrangement of the basin in the fire box ofthe furnace is so chosen that the gases of combustion are dischargedfrom the fire box in a direction generally opposed to the direction ofspraying the fuel. By this means there results the desired progressiveassociation of the fuel with the oxygen, the fuel first passing throughthe combustion zone where it is partially consumed and preheated beforeadmixture with the richest supply of oxygen.

Although I have shown the basin or bowl circular in shape for a domesticheater, it is to be understood that it may be elongated or otherwisechanged for other heaters. In such cases the air is admitted into thebowl in accordance with the principles of the invention as hereinabovedisclosed.

I claim as my invention:

1. A combustion apparatus adapted to be placed in a fire box of afurnace comprising a circular bowl having a large tangential inlet for asupply of low pressure air, an inwardly directed lip on the top of saidbowl above said inlet, and a nozzle for spraying oil into the bowl, saidnozzle being mounted above the bowl and being positioned to direct oildownwardly and laterally to impinge in the bowl on the air substantiallyin front of said inlet.

2. A combustion apparatus adapted to be placed in a fire box of afurnace comprising a circular bowl having a large tangential inlet for asupply of low pressure air and having a concave interior side wall, anda nozzle placed above the bowl and to the bowlside of the inlet, saidnozzle being positioned to spray fuel into the bowl to impinge on theair substantially in front of the inlet.

3. A combustion apparatus adapted to be placed in a fire box of afurnace comprising a circular bowl having a large tangential inlet for asupply of low pressure air and having a concave interior side wall, anda nozzle placed above the bowl at the bowl-side of the inlet and outsideof the circular opening of the bowl, said nozzle being positioned tospray fuel into the bowl to impinge on the air substantially in front ofthe inlet.

4. A combustion apparatus adapted to be placed inside a fire box of afurnace compris ing a bowl having an innerundercut side wall and an airinlet in the wall substantially tangential to the wall, and a nozzleadapted to spray fuel into the bowl substantially in front of the inlet,said nozzle being located above the bowl and on the bowl-side of theinlet.

5. A combustion apparatus adapted to be placed inside a fire box of afurnace comprising a bowl having an inner undercut side wall and a wallinlet substantially tangential to the wall, and a nozzle adapted tospray fuel into the bowl substantially in front of the inlet, saidnozzle being located above the bowl and on the bowl-side of the inlet,and being located outside the opening of the bowl.

6. A burner bowl comprising, in combination, a circular bowl having anundercut inner side wall provided with a tangential air inlet, adraining reservoir beneath said bowl, there being a hole in the bottomofthe bowl communicating with said reservoir, an upwardly extending dripboard projecting outwardly from the top of said bowl, said board andinlet being substantially side by side whereby the bowl may be placedwith the drip board under a nozzle and the nozzle may direct spray intothe bowl substantially in front of the inlet, said board serving todirect drippings from the nozzle into the bowl for drainage into thereservoir.

7 The combination of a house-heating furnace having a combustion chamberprovided with a fire doorway, said furnace also having an ash pitopening, a combustion bowl in, the lower portion of said combustionchamber, a conduit extending through the ash pit opening and directlvconnected to said bowl for supplying a relatively large volume oflowpressure air to the bowl, a nozzle located adjacent to the firedoorway and at one side of and above the combustion bowl for spraying amixture of oil and air down into said bowl, fuel-supplying meansextending through said fire doorway and connected to said nozzle, andignition means projecting through said fire doorway and located adjacentto and below the nozzle and in proximity to the spray discharged fromthe nozzle.

8. In an oil burning apparatus, a circular combustion bowl having atangential air inlet, and means above said bowl for discharging acombustible mixture into the bowl at a point near the air inlet.

9. The combination of a house-heating furnace having a fire door openingand an ashpit door opening, abowl supported within the furnace, saidbowl being small enough for introduction through one of said openings a10 relatively large air supply conduit entering the furnace through theashpit door opening and being connected to the bowl for delivering alarge volume of low-pressure air horizontally into the bowl, andfuel-feeding means entering the furnace through the fire door openingand provided with a nozzle located relatively close to the fire dooropening for discharging fuel downwardly into the bowl.

In testimony whereof, I have hereunto affixed my signature.

GUSTAF DAVID SUN DSTRAND.

